1. Field of the Invention
The present invention is directed toward an apparatus for extremely compact, efficient, durable, reliable, and cost-effective opening and closing of a flow control valve. In particular, the present invention provides a device having an output that rotates with reduced speed and increased torque relative to its input through the low friction, rolling engagement of its members.
2. Background Information
The ability to control flow of liquids, gasses, slurries, and other mixtures is vital to industries and economies throughout the world. Industries dependant on flow control technology range from water/wastewater and food/beverage to chemical and petroleum. Consequently, the applications range from complete environmental control inside indoor factories to harsh, outdoor environmental conditions. Thus, the vitality of a wide range of industries depends on reliable, efficient, and cost-effective methods of flow control.
In order to control and divert the flow of its respective matter, each of these industries depends on appropriate flow control valves designed for its particular application as well as appropriate methods and devices for their actuation. The typical actuation package includes a mechanical valve actuator driven by manual, electric, pneumatic, or hydraulic means. The mechanical valve actuator is typically in the form of a device for increasing the torque of the driving means while applying it to the stem of the flow control valve resulting in opening or closing the valve. These actuation devices must be capable of precisely, efficiently, and reliably opening and closing the flow control valves in a variety of positions and atmospheric conditions. Likewise, the device must be safe for the application and as cost-effective as the application will allow.
The mechanical actuation devices currently on the market utilize conventional torque-increasing technology such as spur, helical, bevel, and worm gears systems. However, a number of inherent deficiencies exist in these systems, which are well known in the art. For instance, in selecting the proper system, a trade-off exists between mechanical efficiency and size of the system. Furthermore, regardless of which system is selected, the inherent high-friction nature of these traditional systems causes inefficiency as well as the possibility of self-destruction. Additionally, sizing and material selection problems exist in that each of these systems must be designed for maximum loading (including shock loads) on each individual tooth. Finally, manufacturing traditional mechanical actuation devices is expensive, time consuming, and inflexible because of the nature of traditional manufacturing processes used to produce both housings and component parts that make-up these currently existing systems.
Significantly, it is well known in the art that one must consider whether efficiency or size of the system is more important. It is well known that spur and helical gear systems are the most efficiently operating traditional systems, but they are inherently large because of the way they must be aligned in order to operate properly. Conversely, bevel and worm gear systems are more compact in their alignment but operate at far inferior efficiencies because of the excessive friction and heat generated in these systems.
Although efficiencies are much greater in spur and helical gear devices, the efficiency and performance of these devices are still detrimentally impacted by the sliding frictional forces generated during their operation. In order to transfer torque, both helical and spur gears depend on the sliding engagement of individual gear teeth. It is well known that this sliding produces high frictional forces between the teeth, which can lead to total destruction of the system if not continuously and properly lubricated.
Furthermore, proper transfer of torque in these traditional systems is totally reliant on the strength of each individual gear tooth. As the input member of the system rotates at a given torque, the force from each single tooth of the input is transferred, one at a time, to each single tooth of the mating gear. As a result, each individual tooth must be designed to transfer the entire force of the system including any shock forces that may be introduced at any particular time. Additionally, any tooth breakage can lead to catastrophic failure of the entire system.
Finally, traditional means of manufacturing housing and components of current mechanical actuation devices are not only expensive and time consuming to set up and modify, but they are also expensive and time consuming to manufacture and produce. The housing for the traditional gear system consists of two or more cast parts assembled together; therefore, in order to either originally produce housings or modify existing designs, either new molds must be manufactured or modifications must be made to existing molds. Likewise, expensive tooling and highly skilled personnel are required for both the gears themselves and other major components of a standard gearbox.
In view of the limitations of products currently known in the art, a tremendous need exists for a valve actuation device that is compact, efficient, durable, reliable, and cost-effective. Applicant's invention, by its novel design provides a solution in view of currently available devices.